I. Infringement of Patents

Section 9 Patent Act provides for the basic right of patentee to exclusively use the invention subject to the patent and to forbid others from using it. To find out whether a third party infringes a patent one has to determine the scope of protection of such patent and to establish that the challenged device actually falls within this scope.

1. Scope of a Patent

The definition of how to determine the scope of protection of a patent is prescribed in Section 14 Patent Act. According to this provision the extent of protection conferred by a patent (or patent application) has to be determined by the terms of the claims, however, using the description and drawings to interpret such claims. German courts have continuously stated that they apply the protocol on the interpretation of Article 69 European Patent Convention in this context. This protocol makes clear that in determining the scope of a patent a balance must be struck between the rights of a patentee and the interests of the public at large in a reasonable degree of certainty. This means in German practice that in interpreting the scope of a patent one may not aim at the literal language of the claims alone but, on the other hand, may not invoke everything mentioned in the patent document.

2. Claim Interpretation

The claims of a patent are the starting point for interpretation as well as the decisive basis for determining the extent of protection. Claim 1 of a patent is considered to be the main claim of which the following claims usually derive as subclaims. As a patent comprises an abstract technical teaching and as the claims setting forth this technical teaching are drafted with a view to a person skilled in the art, any interpretation has to be made under the aspect of technique and not semantic. However, only the knowledge available at the time of the filing of the application can be taken into account by a person skilled in the art.

To interpret the claims of a patent, the description and the drawings shall be used. This means that they have always to be checked but can not extend the scope of protection if the claims do not make reference to elements mentioned in the description or the drawings. If there is a contradiction as to the scope of protection between the claim and a drawing the claim always prevails.

To interpret a patent one has further to distinguish between the two types of patents, product and process patents. As far as product claims are concerned the patent covers all infringing products independent of how they were produced. On the other hand, a product by process claim only protects products which have been manufactured using the patented process.

3. Infringing Acts

A patent is clearly infringed if the challenged device or process is identical to the invention covered by the patent, i.e. if it falls directly under the claims of the patent. However, the protection granted is not limited to the devices and processes covered by the literal terms of the claims. Protection is also extended to equivalents because no-one is in the position to draft claims in a way that will protect against all possible infringing acts. The doctrine of equivalence covers all means that have an effect similar to the means covered by the patent claim, if a person skilled in the art will through his recognition of a specific means used to achieve a specific effect find a different means that achieves the same effect. Again the knowledge at the date of application or the priority date is decisive. To determine whether an equivalent infringement is given is one of the most difficult and disputed issues in practice.

The Federal Supreme Court has established two prerequisites for the extension of a patent claim to equivalent means. First, the means used by the infringer must have the same technical function to reach the same technical result. This would no longer be the case if both means serve different tasks. Second, the means are deemed equivalent if a person skilled in the art could derive it - as of the day of the application - as obvious from the claims stated by use of description and drawings. Although this is not achieved if finding the equivalent means requires an inventive step by a person skilled in the art, it still fulfils the test if some thinking is necessary to find the equivalent means.

Following this, a defendant in an infringement case may accordingly argue that an equivalent infringement is not present because the allegedly infringing device was obvious in the view of prior art. Further, the defendant may bring forward that the device in dispute would represent a patentable invention at the time of filing the patent compared to the patented invention.

II. Legal Procedure of Infringement Cases

1. General

According to Section 139 para. 1 and para. 2 Patent Act a patentee is entitled to sue an infringer for an injunction or for damages before the civil courts. Special chambers at the Regional Courts ("Landgerichte") have exclusive jurisdiction without regard to the value in dispute (Section 143 para. 1 Patent Act).

In any legal action a patentee initiates against an infringer before a civil court he has to show that an infringement is given. Patentee may rely on the assistance of an expert witness who has to be appointed by the court. With regard to product claims it is sufficient for plaintiff to prove that the product of the infringer falls within the scope of the patent. In case of process claims to produce a product plaintiff only has to establish similarity between a product manufactured by the patented process and the allegedly infringing product. The burden of proof to prove the contrary is on the defendant. If plaintiff showed that infringement happened in the past, there exists a prima facie evidence that the defendant will infringe the patent in future as well.

As defense the defendant may bring forward a number of arguments, mainly those which are listed in Section 11 Patent Act. These defenses are personal use (Section 11 No. 1), experimental use (Section 11 No. 2), preparation of a medicine (Section 11 No. 3) and territorial limitations as per Section 11 Nos. 4 through 6 Patent Act. The allegation that the patent is not valid is no defense in an infringement suit because the court in an infringement action does not have jurisdiction to decide about the validity of a patent. The defendant may, however, initiate nullity proceedings with the Federal Patent Court. As the nullity action usually lasts longer than the infringement case the defendant may ask for a suspension of the infringement proceedings. The stay will be ordered by the court, if it takes the view that the nullity action is likely to be successful.

After a judgement is rendered by a court of first instance the defeated party may appeal the decision before the Court of Appeals. On further appeal the case will be finally determined by the Federal Supreme Court.

2. Remedies in an Infringement Suit

The claim of patentee may be directed to different remedies. He may want to receive an injunction against the infringer, claim for damages or compensation or combine these claims in one proceedings.

a) Injunction

The right of patentee for an injunction follows from Section 139 para.1 Patent Act. To receive an injunction against an infringer patentee may apply for a preliminary injunction or a permanent injunction. While the proceedings for a permanent injunction are the regular action before the courts (complaint, defense brief, oral hearing, witnesses etc.) a preliminary injunction enjoining the infringer to use the infringing product any more is the exception. In this proceedings the injunction may be granted ex parte upon the complaint of patentee alone - which, however is unusual in patent infringement cases where normally an oral hearing is scheduled. In this complaint patentee has to show beyond any reasonable doubt that the patent is valid and that it has been infringed prima facie.

b) Damages and Compensation

Section 139 para. 2 Patent Act provides for damages in case of intentional or negligent infringement. As courts consider a culpable infringement already to be given if an infringer could have taken notice of the patent before manufacturing its product, almost every infringement will be considered to have occurred at fault. In order to enable patentee to determine the damages suffered, a court will order the infringer to provide the necessary information regarding the infringing acts (number of products manufactured and shipped, advertisements etc.). Patentee may choose among three options for calculating his damages. He may ask for the actual damages caused by the infringing acts (including lost profits). Second, he may base his claim for damages on usual royalties and, finally, he may claim the profits obtained by the infringer.

In addition to the existing rules of damage assessment it has been established by the Federal Supreme Court that a patentee may also claim compensation according to the rules of unjust enrichment. This claim does not depend on any fault of the infringer and leads to payment of a reasonable royalty only.

While damages are only granted for the time after the grant of the patent has been published, a patentee may claim for a compensation according to Section 33 para. 1 Patent Act, if an infringer has culpably used the subject of a patent application after the application has been published. The claim for compensation would again involve payment of a reasonable royalty, however, less than a usual royalty.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.